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Unit 3: Introduction to Photoshop

Black (CMYK mode; Black is stood for by the letter K). Colours inside colour modes are Notes
saved in their particular colour channels. You can see the channels in the Channels palette.

z File Format: A file format defines the structure and type of data stored in a file. It is a
standard way that digital image is encoded for storage in a computer file. Commonly
used file formats are JPEG, GIF, TiFF, etc.

3.2.3 Bitmap (Raster) and Vector Images

Bitmaps

A bitmap image is a computer file used to store a picture. It consists of tiny blocks called pixels:

a 4 x 3 pixel image = 12 pixels total

Example: The picture above comprises of only 12 pixels so in all actuality might show up
as no more than a modest grey dot. The gaps you see between the pixels don’t truly exist – they
are only indicated for clarity.
Imagine each pixel to be like a tiny square light bulb. Each pixel can be any colour you want and
any brightness.
You can’t illuminate part of a pixel. Real images are of course a lot more complex and consist of
many more pixels.

Example: The example below is still rather blocky and crude, but you can begin to see
how a picture can be made up from pixel building blocks:

Figure 3.7: A Magnified Bitmap Image

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